Process comparison
Flux-Cored Welding vs Submerged Arc Welding
Flux core is a hand-held all-position process; submerged arc is mechanised, flat-position only, and deposits several times more metal per hour.
FCAW vs SAW at a glance
| Flux-Cored Welding | Submerged Arc Welding | |
|---|---|---|
| AWS designation | FCAW — Flux-Cored Arc Welding | SAW — Submerged Arc Welding |
| Filler delivery | Tubular wire with flux inside, with or without gas. | Arc buried under granular flux, mechanised. |
| Polarity | DCEP for gas-shielded wires; DCEN for most self-shielded wires | DCEP most commonly; DCEN for higher deposition; AC on multi-wire systems to control arc blow |
| Typical amperage | 70–450 A depending on wire size | 300–1500 A, and higher on multi-wire installations |
| Typical voltage | 22–30 V | 25–45 V |
| Positions | All positions with 71T wires; 70T flat-and-horizontal wires exist for high deposition | Flat and horizontal fillet only — the flux will not stay in place otherwise |
| Deposition rate | The highest of the manual arc processes | The highest of any common arc process, up to 100 lb/hr on multi-wire systems |
| Shielding | Flux only (self-shielded) or flux plus external gas (gas-shielded) | Granular flux blanket, no gas |
| Skill level | Similar to MIG, with slag removal added | Mechanised or automatic; the skill is in setup and procedure rather than torch handling |
| Slag | Yes — chip between passes | Yes — chip between passes |
Which should you use?
Both hide the arc behind a flux, but they operate at different scales. Flux-cored welding is hand-held, works in every position and suits varied joints. Submerged arc buries the arc under a granular flux blanket, which lets it run at current densities no open-arc process can reach — 15 to 30 pounds per hour on a single wire, over 100 on multi-wire systems — but only in the flat position, only on long regular seams, and only with mechanised equipment. SAW wins whenever the work can be positioned and the seams are long enough to justify setup.
Choose flux-cored welding when
- Varied joints and out-of-position work
- Hand-held flexibility
- Short welds and field erection
- Smaller shops without positioning equipment
Choose submerged arc welding when
- Long, regular seams on heavy plate
- Pressure vessel and pipe mill production
- Work that can be positioned flat or rotated
- Corrosion-resistant cladding over large areas
Strengths and limitations
Flux-Cored Welding
Advantages
- Highest deposition rate of the manual arc processes
- Self-shielded wire works outdoors where MIG cannot
- Deeper penetration than solid MIG wire at the same current
- Handles thicker plate in fewer passes
Limitations
- Slag must be chipped between passes
- Produces noticeably more fume than solid wire, so ventilation matters
- Self-shielded wire has lower toughness and is usually thickness limited
- Gas-shielded wire still cannot be used in wind
Submerged Arc Welding
Advantages
- Deposition rates far beyond any open-arc process
- No arc flash, no spatter and very little fume at the operator's position
- Deep penetration, so thick joints need less preparation
- Highly repeatable weld quality on long seams
Limitations
- Flat and horizontal fillet positions only
- The arc cannot be seen, so the operator relies on instruments and procedure
- Equipment is large and not portable
- Only practical on long, regular seams — not for short or intricate welds
Flux-Cored Welding vs Submerged Arc Welding — common questions
Why can submerged arc only weld flat?
The granular flux blanket is held in place by gravity alone. Out of position it simply falls off the joint, leaving the arc unshielded.
How much faster is submerged arc?
A single SAW wire typically deposits 15 to 30 pounds per hour, and multi-wire installations exceed 100. That is several times what a welder achieves with hand-held flux-cored wire.
Is submerged arc safer?
In some respects, yes. There is no arc flash and very little fume or spatter at the operator's position because the flux covers the arc. It brings its own hazards: hot slag, heavy equipment and flux dust.
Can a small shop use submerged arc?
It is rarely economical. SAW needs mechanised travel, flux handling and recovery, and long regular seams to amortise setup. For varied work, flux core is the practical choice.
Full process guides
Flux-Cored Welding (FCAW)
Flux-cored welding feeds a tubular wire with flux inside, combining MIG's continuous feed with stick's slag shielding — available gas-shielded for quality or self-shielded for wind.
Submerged Arc Welding (SAW)
Submerged arc welding buries the arc under a blanket of granular flux, giving enormous deposition rates with no visible arc, no spatter and no arc flash — the process for heavy plate and long seams.